1. Field of the Invention
The present invention pertains generally to tracking devices. More particularly the present invention pertains to an optical tracking device for use in a computer and/or electronic control system.
2. Discussion of Background Art
Two Dimensional (2D) Tracking Devices
Currently, some of the 2D tracking devices used to move a cursor on a computer display or within an electronic control system are a Mouse, a Track-Ball, a Track-Stick, and an Electro-Static Sensor. While these system all can move the cursor, they are ergonomically inefficient since they require the small muscles of a user's hand and wrist to continuously work in order to move the mouse, spin the track ball, move the track stick, or drag a finger on the electro-static surface. As a result, when these devices are used for more than a short time the user's hand and wrist muscles become fatigued and pain can result. Prolonged use may lead to repetitive strain injuries.
Three Dimensional (3D) Tracking Devices
Many 3D tracking devices not only suffer from the 2D tracking device problems described above, but also require that the user activate buttons or additional keyboard controls to achieve 3D cursor movement. Since such systems lack simultaneous cursor control in all three degrees of freedom, an unnatural and awkward interface is presented to a user.
For example, a track-ball by itself only allows motion in 4 directions (side-to-side, and back-to-front) resulting in only two degrees of motion. The track-ball requires an additional button for generating any up-and-down cursor movement (i.e. pressing the left button and rolling the track ball forward can be used to move the cursor up-and-down). Track-sticks with a vertical position slide type of device have also been used; however, these devices lack precision in controlling the vertical position, are too large for laptop computers, and require that a user's hand be totally dedicated to the track-stick, thus restricting the user's ability to maintain control of the cursor while moving a hand between a key board and the track-stick.
Other 3D tracking devices, such as those that use gloves or other sensors which measure electrical properties such as resistance and parameterize them to generate location and motion data, provide a more natural feel to the user, but are typically very bulky, are difficult to use, and are quite expensive.
What is needed is a less expensive and more ergonomically efficient apparatus and method for 3D tracking.